The drive train is an integral part of the base unit and provides either front- or rear-wheel drive for the scooter.  Front-wheel drive is usually found on smaller scooters designed primarily to be used indoors or outdoors on flat, paved surfaces.  The motor of the front-wheel drive scooter is located over the front wheel and drives only that wheel.  Because of the motor and wheel configuration, front-wheel drive scooters are usually direct-drive units, eliminating chains and belts.  This means that front-wheel drive models generally have smaller motors and that the front wheel pulls the weight of the unit and the rider.  Consequently, these types of scooters have a lesser capacity to move their load than do rear-wheel drive models, and are therefore less capable of handling hills, curb cuts, and other outdoor terrain.  Front-wheel drive scooters often have a shorter range, less speed and power, and a smaller rider weight capacity.  These same factors, however, usually result in a scooter that is smaller than rear-wheel drive models, more maneuverable, more capable of fitting in tighter spaces, and more likely to be compatible with van and bus wheelchair lifts.

Conversely, rear-wheel drive scooters are powered by motors connected to the rear axle, either via a chain, a belt, a transaxle unit, or some combination.  Because the scooter is driven by the rear wheels, they push the combined weight of the unit and the rider, rather than pull it.  The combined weight of the rider, the motor, and the batteries over the rear wheels, generally create better traction than that usually provided by front-wheel drive models.  The increased traction combined with the more powerful motors used on rear-wheel drive scooters results in better climbing ability.  Rear-wheel-drive scooters also have a greater maximum speed, a longer traveling range between battery charges, and a larger rider weight capacity.  These scooters have a wider wheel base and a greater overall length, making them less maneuverable and rendering some models unsuitable for indoor use.  They may also be too large for van or bus lifts.

Front- or rear-wheel drive does not necessarily determine whether a scooter is powerful enough to meet the user's needs, nor does the horsepower of the motor.  The torque of a motor is more often a determining factor. Most scooters use permanent magnet motors, some with lower torque than others.  Lower torque motors frequently provide greater speed on flat, smooth surfaces, while higher torque motors may seem slow in that environment.  However, the higher torque motor will generally offer more power for climbing hills and negotiating other outdoor terrain.  Again it is essential, when evaluating scooters, to keep the scooter’s primary intended use in mind.

Source: ABLEDATA Fact Sheet on Scooters